BACKGROUND OF THE DISCLOSURE
1. Field of the Disclosure
[0001] The present disclosure relates to a compressor, and particularly, to a scroll compressor.
2. Background of the Disclosure
[0002] In a scroll type compressor, a motor part formed as a rotary motor is installed inside
a closed casing, a compression unit including a fixed scroll and an orbiting scroll
is installed on one side of the motor part, and the motor part and the compression
part are connected by a rotating shaft so that a rotational force of the motor part
is transmitted to the compression unit. The rotational force transmitted to the compression
unit causes the orbiting scroll to perform an orbiting movement with respect to the
fixed scroll to form a pair of two compression chambers including a suction chamber,
an intermediate compression chamber and a discharge chamber, so that a refrigerant
is sucked into both compression chambers and compressed and simultaneously discharged.
[0003] Such a scroll-type compressor is provided with a rotation preventing mechanism for
preventing rotation of the orbiting scroll. As the rotation preventing mechanism,
an Oldham ring or a pin-and-ring may be applied.
[0004] The pin-and-ring type is advantageous compared with the above-mentioned Oldham ring
type in that reliability is improved due to enhancement of durability of the rotation
preventing mechanism and an increase in weight of the compressor due to the rotation
preventing mechanism is suppressed. Meanwhile, the pin-and-ring type is relatively
disadvantageous in terms of assembly since a plurality of pins and rings must be installed
in each of the orbiting scroll and a member in contacting therewith. Therefore, research
has been continuing to replace the pin-and-ring type by improving a material of the
Oldham ring.
[0005] Particularly, when the scroll compressor is applied to an automotive air conditioning
system, the Oldham ring may be formed of aluminum material in consideration of the
weight and workability of the compressor. When aluminum is applied to the Oldham ring,
the weight of the Oldham ring may be lowered and workability and productivity may
be improved.
[0006] However, when the weight of the compressor is considered, it is advantageous to manufacture
the peripheral orbiting scroll, a main frame, or the fixed scroll, as well as the
Oldham ring, and in this case, since the material of the aluminum Oldham ring and
a material of a relative frictional surface are the same, friction characteristics
are significantly degraded. Recently, a technique for improving wear reliability of
a key portion of the Oldham ring has been introduced.
[0007] US 2017-0234313 A is a technique for increasing wear resistance, while reducing the weight of the Oldham
ring by forming a ring portion and a key portion of the Oldham ring with different
materials.
[0008] KR 10-1997-0021751 is a technique for surface-treating the Oldham ring to suppress the Oldham ring from
being welded to the orbiting scroll or the fixed scroll.
[0009] However, in the conventional scroll compressor as described above, when the ring
portion and the key portion of the Oldham ring are made of different materials in
consideration of the weight and reliability of the compressor, a manufacturing process
of post-assembling the ring portion and the key portion may be complicated. Also,
in this case, a sectional area of a portion where the ring portion and the key portion
are assembled may be reduced, so that a bearing strength against the key portion is
weakened, and reliability with respect to the bearing may be lowered. Also, in this
case, a gap is generated at a joint portion of the ring portion and the key portion
due to a machining error or an assembly error between the ring portion and the key
portion, and when the compressor is driven, the key portion is warped relative to
the ring portion so that the orbiting scroll is pushed in a circumferential direction,
resultantly forming a gap between the wraps to increase compression loss. Also, coefficients
of thermal expansion of the ring portion and the key portion are different from each
other, resulting in separation of the key portion from the ring portion or idling.
[0010] In the conventional scroll compressor, a coating layer may be formed on a surface
of the Oldham ring with a lubricating material or the like. However, manufacturing
cost is increased due to formation of a separate coating layer, and the coating layer
is peeled off or worn when it is used for a long time to damage the Oldham ring or
increase friction loss.
SUMMARY OF THE DISCLOSURE
[0011] Therefore, an aspect of the detailed description is to provide a scroll compressor
having an overall weight reduced by reducing a weight of an Oldham ring, when the
Oldham ring is applied.
[0012] Further, another aspect of the detailed description is to provide a scroll compressor
in which an Oldham ring is formed of the same material as that of a frame to which
the Oldham ring is coupled, an orbiting scroll, or a fixed scroll.
[0013] Further, another aspect of the detailed description is to provide a scroll compressor
in which both members to which an Oldham ring is coupled are formed of the same material
and the Oldham ring is formed of the same material as that of the both members to
which the Oldham ring is coupled.
[0014] Further, another aspect of the detailed description is to provide a scroll compressor
in which a ring portion and a key portion forming an Oldham ring are formed of the
same material.
[0015] Further, another aspect of the detailed description is to provide a scroll compressor
capable of enhancing workability and productivity for an Oldham ring.
[0016] Further, another aspect of the detailed description is to provide a scroll compressor
in which generation of a gap of an allowable value or greater between a key portion
of an Oldham ring and a key recess of a frame, an orbiting scroll, or a fixed scroll
to which the key portion is coupled is suppressed to increase compressor efficiency.
[0017] Further, another aspect of the detailed description is to provide a scroll compressor
capable of securing a bearing strength of a key portion with respect to a ring portion
forming an Oldham ring, thereby enhance reliability.
[0018] Further, another aspect of the detailed description is to provide a scroll compressor
capable of suppressing idling of a key portion with respect to a ring portion forming
an Oldham ring, thereby enhancing reliability.
[0019] Further, another aspect of the detailed description is to provide a scroll compressor
in which a ring portion and a key portion forming an Oldham ring are formed as a single
body.
[0020] The object is solved by the features of the independent claims. Preferred embodiments
are given in the dependent claims.
[0021] To achieve these and other advantages and in accordance with the purpose of this
specification, as embodied and broadly described herein, a scroll compressor includes:
a first scroll; a second scroll engaged with the first scroll and performing an orbiting
movement; and an Oldham ring including a ring portion formed in a ring shape and a
key portion protruding from the ring portion, wherein the key portion is slidably
coupled to a key recess provided in the second scroll to enable the second scroll
to perform an orbiting movement with respect to the first scroll
[0022] Preferably, the key portion of the Oldham ring is formed of the same material as
the second scroll.
[0023] Here, a wear preventing member formed of a material different from the second scroll
or the Oldham ring may be provided between the key portion and the key recess.
[0024] The wear preventing member may be inserted into the key recess so as to be coupled.
[0025] An escape preventing portion for preventing the wear preventing member from escaping
may be formed between the wear preventing member and a member to which the wear preventing
member is coupled.
[0026] To achieve these and other advantages and in accordance with the purpose of this
specification, as embodied and broadly described herein, a scroll compressor includes:
a first scroll; a second scroll engaged with the first scroll to perform an orbiting
movement to form a compression chamber with the first scroll; and an Oldham ring including
a ring portion formed in a ring shape and a key portion protruding from the ring portion,
wherein the key portion is slidably coupled to a key recess provided in the second
scroll to enable the second scroll to perform an orbiting movement with respect to
the first scroll, wherein a wear preventing member is provided between the key recess
of the second scroll and the key portion of the Oldham ring.
[0027] Here, the key portion of the Oldham ring may be formed of the same material as the
second scroll, and the wear preventing member may be formed of a material different
from the key recess of the second scroll or the key portion of the Oldham ring.
[0028] The key portion and the ring portion of the Oldham ring may be formed of the same
material.
[0029] The key portion and the ring portion of the Oldham ring may be formed as a single
body.
[0030] The wear preventing member, also called friction prevention member, may include a
first reinforcement surface and a second reinforcement surface arranged in parallel
in a radial direction and a connection surface connecting the first reinforcement
surface and the second reinforcement surface.
[0031] Preferably, the connection surface extends from one ends of the first reinforcement
surface and the second reinforcement surface facing each other in the radial direction
to connect the first reinforcement surface and the second reinforcement surface.
[0032] The connection surface may be formed to expand in a circumferential direction, relative
to an interval between the first reinforcement surface and the second reinforcement
surface, and an escape preventing recess into which the connection surface is inserted
to support the wear preventing member in the radial direction may be formed at one
end of the key recess.
[0033] Here, the connection surface may have the same diameter as the interval between the
first reinforcement surface and the second reinforcement surface, and a fixing pin
may be coupled to one end of the key recess to support the connection surface in the
radial direction.
[0034] Here, the connection surface may have the same diameter as the interval between the
first reinforcement surface and the second reinforcement surface, and an escape preventing
recess into which one axial end of the wear preventing member is inserted and supported
may be formed in the key recess.
[0035] Here, the wear preventing member may include a first reinforcement surface and a
second reinforcement surface arranged in parallel in a radial direction and a third
reinforcement surface extending from one axial ends where the first reinforcement
surface and the second reinforcement surface facing each other in a circumferential
direction to connect the first reinforcement surface and the second reinforcement
surface.
[0036] Escape preventing surfaces may be further formed on the first reinforcement surface
and the second reinforcement surface and extend from one facing ends of the first
reinforcement surface and the second reinforcement surface to support the wear preventing
member in the radial direction, and an escape preventing recess may be formed at one
end of the key recess and expand, relative to a width of the key recess, in the circumferential
direction, into which the escape preventing surface is inserted.
[0037] Here, an oil storage recess may be formed to be deeper than a bottom surface of the
key recess in the second scroll, and the oil storage recess may be formed to communicate
with the key recess outside a movement range of the key portion.
[0038] To achieve these and other advantages and in accordance with the purpose of this
specification, as embodied and broadly described herein, a scroll compressor includes:
a casing; a driving motor in which a stator is fixed to an inner space of the casing
and a rotor is rotatably provided in the stator; a first scroll provided on one side
of the driving motor; a second scroll engaged with the first scroll to form a compression
chamber with the first scroll, while performing an orbiting movement, and having a
plurality of first key recesses; a rotating shaft in which one end is coupled to the
rotor of the driving motor and the other end is eccentrically coupled to the second
scroll so as to overlap with the compression chamber in a radial direction; a frame
provided on the opposite side of the first scroll with the second scroll interposed
therebetween and having a plurality of second key recesses; an Oldham ring having
a ring portion located between the frame and the second scroll and a plurality of
key portions protruding from the ring portion and slidably inserted into the first
key recess and the second key recess; and a wear preventing member formed of a material
different from the Oldham ring or the second scroll and provided between the first
key recess or the second key recess and the key portion of the Oldham ring inserted
therein.
[0039] Here, the Oldham ring may be formed of the same material as the second scroll or
the frame.
[0040] The ring portion and the key portion of the Oldham ring may be formed of the same
material and formed as a single body.
[0041] The wear preventing member may be inserted into the first key recess or the second
key recess and an escape preventing portion may be provided between the first key
recess or the second key recess and the wear preventing member inserted therein to
suppress escaping of the wear preventing member from the key recess in the radial
direction.
[0042] In the scroll compressor according to the present invention, since an wear preventing
member is provided between the key portion and the key recess of the frame, the orbiting
scroll, or the fixed scroll into which the key portion is inserted, the Oldham ring
is prevented from being in direct contact with the frame, the orbiting scroll or the
fixed scroll. As a result, the ring portion and the key portion forming the Oldham
ring may be formed of lightweight aluminum, which may reduce the weight of the Oldham
ring and the weight of the compressor to which the Oldham ring is applied.
[0043] Further, according to the present invention, it is possible to prevent the frictional
characteristic due to a friction between the same material from being lowered, even
though the Oldham ring of the scroll compressor according to the present invention
is formed of the same material as that of the frame, the orbiting scroll, or the fixed
scroll to which the key portion of the Oldham ring is coupled. As a result, it is
possible to reduce friction between the Oldham ring and the member to which the Oldham
ring is coupled, thus reducing damage to the Oldham ring or a counterpart member and
reducing a friction loss to thus increase compressor efficiency.
[0044] Furthermore, in the Oldham ring of the scroll compressor according to the present
invention, since the ring portion and the key portion forming the Oldham ring are
formed as a single body, it is easy to manufacture the Oldham ring. In addition, it
is possible to suppress the phenomenon that the key portion of the Oldham ring is
twisted in the key recess of the counterpart member when the compressor is driven,
thereby suppressing the orbiting scroll from being pushed in the circumferential direction,
thereby reducing compression loss caused by a spacing between the wraps. Further,
it is possible to secure strength against a root portion of the key portion protruding
from the ring portion, thereby suppressing damage of the key portion, thereby enhancing
reliability.
[0045] Further, in the forming the Oldham ring of the scroll compressor according to the
present invention, since the ring portion and the key portion forming the Oldham ring
are formed as a single body and formed of the same material, the key portion is prevented
from be excessively deformed or idly rotated even though the Oldham ring is heated
when the compressor is driven. Thus, it is possible to prevent the behavior of the
orbiting scroll from becoming unstable due to the Oldham ring.
[0046] Further, in the scroll compressor according to the present invention, the wear preventing
member is provided between the key portion of the Oldham ring and the key recess of
the frame, the orbiting scroll, or the fixed scroll into which the key portion is
inserted, and a separation prevention portion is formed between one end of the wear
preventing member and the corresponding key recess to fix the wear preventing member.
As a result, it is possible to effectively prevent the wear preventing member from
being separated from the key recess, thereby increasing reliability.
[0047] Further, the separation prevention portion may be easily formed by forming a protrusion
on the wear prevention portion and a recess on the corresponding key recess, or the
wear preventing member may be fixed using a separate fixing pin. When the wear preventing
member is fixed by using a separate fixing pin, the entire radial length of the key
recess including the escape preventing portion may be reduced, and the diameter of
the key recess for the inner circumference may be increased. This may enlarge the
area of the back pressure space formed inside the abovementioned Oldham ring and stably
support the orbiting scroll as much.
[0048] Furthermore, the wear preventing member may be formed to correspond to the circumferential
side surface of the key recess and the bottom surface connecting the both side surfaces
thereof. Accordingly, it is possible to suppress contact between the key portion and
the key recess even at the one axial side surface corresponding to the bottom surface
of the key recess, as well as at both circumferential side surfaces between the key
portion and the key recess. Then, when the behavior of the orbiting scroll is unstable,
the key portion and the key recess are prevented from coming into contact with each
other in the axial direction to cause wearing.
[0049] Further scope of applicability of the present application will become more apparent
from the detailed description given hereinafter. However, it should be understood
that the detailed description and specific examples, while indicating preferred embodiments
of the disclosure, are given by way of illustration only, since various changes and
modifications within the spirit and scope of the disclosure will become apparent to
those skilled in the art from the detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0050] The accompanying drawings, which are included to provide a further understanding
of the disclosure and are incorporated in and constitute a part of this specification,
illustrate exemplary embodiments and together with the description serve to explain
the principles of the disclosure.
[0051] In the drawings:
FIG.1 is a cross-sectional view showing an inside of an electric compressor as an
example of a scroll compressor according to the present invention;
FIG.2 is a cross-sectional view showing a state that an Oldham ring is coupled between
a frame and an orbiting scroll in a compression unit according to FIG.1;
FIG.3 is an exploded perspective view of the compression unit according to FIG.2;
FIG.4 is a perspective view showing a state that a wear preventing member is separated
from an orbiting scroll in the compression unit according to FIG.3;
FIG.5 is a plan view showing a state where a wear preventing member is coupled to
an orbiting scroll in FIG.4;
FIG.6 is a cross-sectional view taken along line " IV-IV" in FIG.5;
FIGS. 7 and 8 are a perspective view showing a state that a frame and a wear preventing
member are separated from each other and a state that the frame and the wear preventing
member are coupled in FIG.3;
FIG.9 is a cross-sectional view showing an example in which an oil storage recess
is provided in a key recess of an orbiting scroll according to the present invention;
FIG.10 is a plan view showing another embodiment of an escape preventing protrusion
of a wear preventing member according to the present invention;
FIGS. 11 and 12 are a perspective view and an assembled plan view showing another
embodiment of an escape preventing portion of a wear preventing portion according
to the present invention;
FIGS. 13 and 14 are a perspective view and an assembled plan view showing another
embodiment of an escape preventing portion according to the present invention; and
FIGS. 15 and 16 are a perspective view and an assembled plan view showing another
embodiment of a wear preventing member according to the present invention.
DETAILED DESCRIPTION OF THE DISCLOSURE
[0052] Description will now be given in detail of the exemplary embodiments, with reference
to the accompanying drawings. For the sake of brief description with reference to
the drawings, the same or equivalent components will be provided with the same reference
numbers, and description thereof will not be repeated.
[0053] Hereinafter, a scroll compressor according to the present invention will be described
in detail with reference to an embodiment shown in the accompanying drawings.
[0054] FIG.1 is a cross-sectional view showing the inside of an electric compressor as an
example of a scroll compressor according to the present invention, and FIG.2 is a
cross-sectional view showing a state that an Oldham ring is coupled between a frame
and an orbiting scroll in a compression unit according to FIG.1.
[0055] As shown in these figures, the scroll compressor according to the present embodiment
includes a driving motor 103 which is a motor part and a compression unit 105 compressing
a refrigerant using a rotational force of the driving motor 103 inside a compressor
casing 101.
[0056] The compressor casing 101 is provided with an intake port 111a to which a suction
pipe is connected and an exhaust port 121a to which a discharge pipe is connected.
A suction space S1 communicates with the intake port 111a and a discharge space S2
communicates with the exhaust port 121a. The driving motor 103 is installed in the
suction space S1, and the compressor of the present embodiment is a low pressure type
compressor.
[0057] The compressor casing 101 includes a main housing 110 in which the driving motor
103 is installed and a rear housing 120 coupled to an opened rear end of the main
housing 110. An inner space of the main housing 110 forms the suction space S1 together
with one side surface of the compression unit 105 and an inner space of the rear housing
120 forms the discharge space S2 together with the other side surface of the compression
unit 105. In the rear housing 120, the above-described exhaust port 121a is formed.
[0058] The main housing 110 has a cylindrical portion 111 formed in a cylindrical shape
and a front end of the cylindrical portion 111 is integrally extended to form a closed
portion 112. The rear end of the cylindrical portion 111 is opened and the rear housing
120 is sealed and coupled.
[0059] Meanwhile, the driving motor 103 constituting a motor part is press-fitted into the
main housing 110. The driving motor 103 includes a stator 131 fixed inside the main
housing 110 and a rotor 132 positioned inside the stator 131 and rotated by interaction
with the stator 131.
[0060] The stator 131 is fixed as a stator core (no reference numeral) is shrink-fitted
to the inner circumferential surface of the main housing. In the rotor 132, the rotating
shaft 133 is press-fitted to the inner circumferential surface of the rotor core (no
reference numeral).
[0061] The rotating shaft 133 is coupled to the center of the rotor 132 and a rear end facing
the compression unit 105 is supported by the frame 140 (to be described) and the fixed
scroll 150 in a cantilevered manner.
[0062] The compression unit 105 includes the frame 140, a fixed scroll (hereinafter referred
to as a first scroll) 150 supported by the frame 140, and an orbiting scroll (hereinafter
referred to as a second scroll) 160 provided between the frame 140 and the first scroll
150 and making an orbiting movement.
[0063] The frame 140 is coupled to the front opening of the main housing 110, the first
scroll 150 is fixedly supported on the rear surface of the frame 140 and the second
scroll 160 is rotatably supported on the rear surface of the frame 140 to perform
an orbiting movement between the first scroll 150 and the frame 140. The second scroll
160 is eccentrically coupled to the rotating shaft 133 coupled to the rotor 132 of
the driving motor 103 and performs an orbiting movement relative to the first scroll
150 to form a pair of two pair of compression chambers V including suction chamber,
an intermediate pressure chamber, and a discharge chamber.
[0064] The frame 140 includes a frame disk plate portion 141 having a disk shape and a frame
side wall portion 142 protruding from a rear side surface toward the first scroll
150 to allow the side wall portion 152 of the first scroll 150 to be described later.
[0065] A frame thrust surface 143 is formed on the inner side of the frame side wall portion
142 and supported by the second scroll 160 to be axially supported. A back pressure
space 144 in which a portion of a refrigerant compressed in the compression chamber
V is filled with oil to support the back surface of the second scroll 160 is formed.
Accordingly, the pressure in the back pressure space 144 forms an intermediate pressure
between the pressure in the suction space S1 and the final pressure (i.e., the discharge
pressure) in the compression chamber V.
[0066] A frame shaft hole 145 through which the rotating shaft 133 passes is formed in the
back pressure space 144 and a first bearing (not shown) is provided on the inner circumferential
surface of the frame shaft hole 145. The first bearing may be made of a bush bearing,
but in some cases it may be a ball bearing. However, since the bush bearing is less
expensive than the ball bearing, it is advantageous not only in cost but also in ease
of assembly and weight and noise reduction.
[0067] On the inner side of the frame thrust surface 143, a second key recess 146 is formed
in which a second key portion 176 of an Oldham ring 170 to be described later is slidably
inserted. Two second key recesses 146 are typically formed at intervals of 180 degrees.
The second key recesses 146 will be described later together with a friction preventing
member.
[0068] Meanwhile, the first scroll 150 may be fixedly coupled to the frame 140 or may be
press-fitted into the casing 110 to be fixed.
[0069] The first scroll 150 has a fixed scroll disk plate portion 151 (hereinafter, fixed
side disk plate portion) 151 having a substantially disk shape and a fixed scroll
side wall portion (hereinafter, first side wall portion) 152 formed at the edge of
the fixed side disk plate portion 151 and coupled to the side wall portion 142 of
the frame 140. On a front surface of the fixed side disk plate portion 151, a fixed
side wrap 153 which is engaged with the orbiting side wrap 162 to be described later
and constitutes the compression chamber (V) is formed.
[0070] A suction flow path (not shown) is formed at one side of the first side wall portion
152 so that the suction space S1 and a suction chamber (not shown) communicate with
each other, and a discharge port 155 communicating with the discharge chamber and
discharging a compressed refrigerant to the discharge space S2 is formed at a central
portion of the fixed side disk plate portion 151.
[0071] Meanwhile, the second scroll 160 is provided between the frame and the first scroll
150, and eccentrically coupled to a rotating shaft 133 to perform an orbiting movement.
[0072] In the second scroll 160, an orbiting scroll disk plate portion (hereinafter, orbiting
side disk plate portion) 161 is formed to have a substantially disc shape, and an
orbiting side wrap 162 engaged with the fixed side wrap 153 to form a compression
chamber is formed on the rear surface of the orbiting side disk plate portion 161.
The orbiting side wrap 162 may have an involute shape together with the fixed side
wrap 153, but it may also have various other shapes.
[0073] On the front surface of the orbiting side disk plate portion 161, a scroll-side thrust
surface 165 corresponding to the frame-side thrust surface 143 and forming a thrust
surface is formed. However, since the second scroll 160 floats against the frame 140
when the compressor is driven, the frame-side thrust surface 143 and the scroll-side
thrust surface 165 are substantially not in contact with each other. Rather, the frame
140 and the second scroll 160 form a thrust surface with the ring portion 171 of the
Oldham ring 170 to be described later.
[0074] A first key recess 166 into which the first key portion 175 of the oval bearing 170
to be described later is slidably inserted is formed in the middle of the scroll-side
thrust surface 165. Two first key recesses 166 are formed at intervals of 180 degrees.
The first key recess 166 is formed with a phase difference of about 90 degrees with
the second key recess 146 in an axial direction projection. The first key recess will
be described later together with the friction preventing member.
[0075] Meanwhile, a rotation preventing mechanism is provided between the frame 140 and
the second scroll 160 to prevent rotation of the second scroll 160. The rotation preventing
mechanism may be installed between the first scroll 150 and the second scroll 160
in some cases. Hereinafter, an example in which the rotation preventing mechanism
is provided between the frame 140 and the second scroll 160 will be described as an
example.
[0076] The rotation preventing mechanism may be a pin-and-ring type as described above,
or an Oldham ring type. The present embodiment relates to the case where the Oldham
ring e is applied.
[0077] The Oldham ring includes a ring portion 171 formed in an annular shape and a plurality
of first key portions 175 and a plurality of second key portions 176 protruding from
both side surfaces in the axial direction of the ring portion 171. The structure of
the Oldham ring will be described later together with the friction preventing member.
[0078] In the figure, the reference numeral 137 is a balance weight.
[0079] The scroll compressor according to this embodiment operates as follows.
[0080] That is, when power is applied to the driving motor 103, the rotating shaft 133 rotates
together with the rotor 132 to transmit a rotational force to the second scroll 160,
and the second scroll 160 makes an orbiting movement by the Oldham ring which is a
rotation preventing mechanism, and thus, the compression chamber V is continuously
moved toward the center side and the volume of the compression chamber V is reduced.
[0081] The refrigerant flows into the suction space S1 through the intake port 111a and
the refrigerant introduced into the suction space S1 passes through a flow path formed
in the outer circumferential surface of the stator 131 and the inner circumferential
surface of the main housing 110 or an air gap between the stator 131 and the rotor
132 and is sucked to the compression chamber V through a suction flow path 154.
[0082] At this time, a part of the refrigerant sucked into the suction space S1 through
the intake port 111a first comes into contact with closed portion 112 which is the
front surface of the main housing 110, before passing through the driving motor 103.
Accordingly, the closed portion 112 is heat-exchanged with the cold suction refrigerant
and cooled, thereby dissipating heat in an inverter module (not shown) attached to
the closed portion 112 of the main housing 110.
[0083] The refrigerant sucked into the compression chamber V through the suction space S1
is compressed by the first scroll 150 and the second scroll 160 and is discharged
into the discharge space S2 through the discharge port 155. Oil of the refrigerant
discharged to the discharge space S2 is separated at the discharge space S2 and the
refrigerant is discharged to the refrigerating cycle through the exhaust port 121a
while the oil is collected at a lower portion of the discharge space S2 and supplied
to the respective bearing surfaces or to the compression chamber through an oil flow
path (not shown).
[0084] At this time, a part of the oil flows into a space between the frame 140 and the
second scroll 160 to lubricate between the Oldham ring 170 and the frame 140 to which
the Oldham ring 170 is coupled or the second scroll 160.
[0085] Meanwhile, the scroll compressor as described above is widely applied not only to
an air conditioning system in a building but also to an air conditioning system in
a vehicle. Scroll compressors may increase compressor efficiency by reducing a weight
of a moving member, similarly to other compressors. Particularly, when installed in
a vehicle, it is advantageous to reduce the weight of the compressor since the weight
of the entire compressor as well as the rotating member is related to the weight of
the vehicle.
[0086] Accordingly, in a scroll compressor (generally called an electric scroll compressor)
applied to a vehicle, a casing, a frame, a fixed scroll and an orbiting scroll as
well as an Oldham ring may be made of a lightweight material such as aluminum (aluminum
alloy).
[0087] However, as described above, when the Oldham ring and the frame or the orbiting scroll
contacting the Oldham ring is formed of an aluminum material, friction characteristics
depending on the same material may be deteriorate, unlike cast iron.
[0088] Taking this into consideration, it is considered to form the ring portion and the
key portion of the Oldham ring by different materials and assembled or to form the
entire Oldham ring of the same material and form a coating layer for improving friction
characteristics on the surface of the Oldham ring. However, these methods have limitations
in workability and reliability as described above.
[0089] Accordingly, the present invention is to improve the workability of the above-mentioned
bearing by forming the entire Oldham ring with the same kind of material and forming
the frame or the orbiting scroll to which the Oldham ring is coupled with the same
material as the Oldham ring, while preventing deterioration of friction characteristics
according to the same material, to ensure the reliability of the compressor.
[0090] FIG.3 is an exploded perspective view of the compression unit according to FIG.2,
FIG.4 is a perspective view showing a state that a wear preventing member is separated
from an orbiting scroll in the compression unit according to FIG.3, FIG.5 is a plan
view showing a state where a wear preventing member is coupled to a key recess of
an orbiting scroll in FIG.4, and FIG.6 is a cross-sectional view taken along line
" IV-IV" in FIG.5.
[0091] As shown in the figure, the frame 140, the second scroll 160, and the Oldham ring
170 are all formed of an aluminum material that is lighter than cast iron. The specific
gravity of the cast iron is about 7.85, and the specific gravity of the aluminum alloy
is about 2.8. Accordingly, when the frame, the second scroll, and the Oldham ring
are all made of aluminum, the weight of the compressor may be greatly reduced.
[0092] The Oldham ring may include a ring portion 171 formed in an annular shape and a first
key portion 175 and a second key portion 176 protruding from both side surfaces of
the ring portion 171 in the axial direction. A plurality of first key portions 175
are formed on one axial side surface of the ring portion 171 and plurality of second
key portions 176 are formed on the other axial side surface of the ring portion 171.
The plurality of first key portions 175 and the second key portions 176 are formed
at intervals of 180 degrees along the circumferential direction so that the first
key portions 175 and the second key portions 176 are formed at intervals of 90 degrees
with respect to each other.
[0093] The first key portion 175 and the second key portion 176 are each formed in a rectangular
cross-sectional shape extending in the radial direction. However, the first key portion
175 and the second key portion 176 may be formed to have a square cross section or
a shape having a similar length in some cases. This will be explained later with the
key recess.
[0094] The ring portion 171 and the key portions 175 and 176 are formed as a single body.
That is, the first key portion 175 and the second key portion 176 are formed integrally
with the ring portion 171. Accordingly, the ring portion 171 and the key portions
175 and 176 are made of the same kind of material, that is, the entire Oldham ring
is formed of an aluminum material.
[0095] A plurality of first key recesses 166 corresponding to the first key portion 175
of the Oldham ring 170 are formed at the second scroll 160 and a plurality of second
key recesses 146 corresponding to the second key portion 176 of the Oldham ring 170
are formed at the frame 140. The plurality of first key recesses 166 and the plurality
of second key recesses 146 are formed on the surfaces facing each other.
[0096] The first key recess 166 of the second scroll 160 and the second key recess 146 of
the frame 140 are formed to be sufficiently long in a radial direction as compared
with the first key portion 175 and the second key portion 176 of the Oldham ring 170
and are formed so as to have a width substantially in contact with the side surfaces
of the first key portion 175 and the second key portion 176 in the circumferential
direction.
[0097] The first key portion 175 and the second key portion 176 of the Oldham ring 170 slide
in the radial direction to the first key recess 166 of the second scroll 160 and the
second key recess 166 of the frame 160, while transferring a force in the circumferential
direction.
[0098] Therefore, in the present embodiment, the friction preventing member 180 may be also
called wear prevention member and may be inserted between the circumferential side
surface of the first key portion 166 and the circumferential side surface of the first
key portion 175 and between the circumferential side surface of the second key recess
146 and the circumferential side surface of the second key portion 176, respectively.
The friction preventing members 180 may be formed of a material having rigidity higher
than that of the second scroll 160 or the frame 140 or the Oldham ring 170, that is,
made of a material different from that of the second scroll 160, the frame 140, or
the Oldham ring 170.
[0099] Then, when the first key portion 175 and the second key portion 176 slide relative
to the first key recess 166 and the second key recess 146 respectively, it is possible
to prevent the key portion, which is a homogeneous material, from coming into direct
contact with the key recess. Then, the second scroll 160, the frame 140, or the Oldham
ring 170 are all formed of a lightweight material and wearing of the key recess of
the second scroll 160 or the frame 140 or the key portion of the Oldham ring 170 may
be suppressed.
[0100] Hereinafter, the wear preventing member and the key recess into which the wear preventing
member is inserted will be described in detail. The first key recess, the first key
portion, and the friction preventing member provided therebetween are the same as
the second key recess, the second key portion, and the friction preventing member
provided therebetween, respectively. Therefore, the first key recess and the first
key portion, and the friction preventing member inserted between the first key recess
and the first key portion will be mainly described.
[0101] Referring to FIGS. 3 and 4 again, the first key recess 166 is formed in a slit shape
having a predetermined length in the radial direction. The first key recess 166 has
a first key recess surface 166a and a second key recess surface 166b facing each other
in the circumferential direction, and a front surface forming the bottom surface in
the axial direction forms a third key recess surface 166c and the opposite rear surface
forms an opening surface 166d in the axial direction. An outer opening surface 166e
is formed at the outer end to allow the first key portion 175 to enter and exit and
an inner opening surface 166f is formed at the inner end to communicate with an escape
preventing recess 167 to be described later.
[0102] As illustrated in FIG.5, the first key recess surface 166a and the second key recess
surface 166b are formed parallel to each other in the radial direction, and an interval
L1 (hereinafter, first space) between the first key recess surface 166a and the second
key recess surface 166b is shorter than a radial length L2 (hereinafter, second length)
of the first key recess surface 166a and the second key recess surface 166b.
[0103] The inner opening surface 166f may be formed to be closed in a semicircular shape
at the inner ends of the first key recess surface 166a and the second key recess surface
166b. However, in this embodiment, the escape preventing recess 167 is formed so as
to fix the friction preventing member 180 to the inner opening surface 166f. The escape
preventing recess 167 and an escape preventing protrusion 182 of the friction preventing
member 180 to be described later constitute an escape preventing portion.
[0104] The escape preventing recess 167 extends from the inner end of the first key recess
surface 166a and the second key recess surface 166b and is formed closer to a circle
than a semicircle. Accordingly, an inner diameter L3 of the escape preventing recess
167 is formed to be larger than the first interval L1, and a length of a virtual line
connecting a portion to which one end of the escape preventing recess 167 is connected
in the first key recess surface 166a and a portion to which the other end of the escape
preventing recess 167 is connected in the second key recess surface 166b is formed
to gradually increase to a radius of the escape preventing recess. In other words,
a maximum circumferential length L3 between the inner wall surfaces 167a of the escape
preventing recess 167 is formed larger than the first interval L1.
[0105] The first key portion 175 includes a first key surface 175a corresponding to the
first key recess surface 166a and a second key surface 175b corresponding to the second
key recess surface 166b. Accordingly, the first key portion 175 may have a square
or rectangular cross-sectional shape when projected in the axial direction.
[0106] When the first key portion 175 is formed to be square (or the same as the radial
width of the ring portion), the length of the first key portion 175 in the radial
direction is shortened. Then, the inner diameter of the ring portion 171 may be enlarged
as the radial length of the first key portion 175 is shortened. Then, a back pressure
space 144 of the frame 140 formed inside the ring portion 171 may be widened.
[0107] Meanwhile, when the first key portion 175 is formed in a rectangular shape (or is
formed larger than the radial width of the ring portion), the length of the first
key portion 175 in the radial direction becomes longer and shaking of the Oldham ring
170 is reduced to suppress leakage from the compression chamber.
[0108] The radial length L4 of the first key portion 175 is shorter than the radial length
of the first key recess 166 having the second length L2. The first key portion 175
slides in a space between the first key recess surface 166a and the second key recess
surface 166b so that the first key portion 175 does not move to the inside of the
escape preventing recess 167. If the first key portion 175 moves to the inside of
the escape preventing recess 167, the first key portion 175 preferably moves so as
to penetrate only less than 1/2 of the radial length L4 of the first key portion 175
to stably support the first key portion 175.
[0109] Meanwhile, the friction preventing member 180 may be formed to be bent in a U-shaped
cross-sectional shape on the whole or by molding a polymer material. That is, the
friction preventing member 180 may include a first reinforcement surface 181a and
a second reinforcement surface 181b arranged in parallel in the radial direction and
a connection surface 182 connecting the first reinforcement surface 181a and the second
reinforcement surface 181b to form an escape preventing portion.
[0110] The first reinforcement surface 181a and the second reinforcement surface 181b are
in close contact with the first key recess surface 166a and the second key recess
surface 166b so that an inner side surface of the first reinforcement surface 181a
and an inner side surface of the second reinforcement surface 181b may correspond
to each other with a predetermined lubricating interval t the first key surface 175a
and the second key surface 175b.
[0111] For example, as illustrated in FIGS. 4 and 5, the connection surface 182 is bent
from one end of the first reinforcement surface 181a and one end of the second reinforcement
surface 181b facing each other to extend to connect the first reinforcement surface
181a and the second reinforcement surface 181b. The first reinforcement surface 181a
and the second reinforcement surface 181b may be brought into close contact with the
first key recess surface 166a and the second key recess surface 166b due to an elastic
force of the connection surface 182.
[0112] The outer surface of the connection surface 182 is formed so as to be in close contact
with the inner circumferential surface of the escape preventing recess 167. For example,
an inner diameter L3', which is a maximum distance in the circumferential direction
formed by the connection surface 182, is formed to be greater than an interval L1'
formed by each inner side surface of the first reinforcement surface 181a and the
inner side surface of the second reinforcement surface 181b. Accordingly, the outer
circumferential surface of the connection surface 182 is in close contact with the
inner circumferential surface of the escape preventing recess 167 to form an escape
preventing protrusion so that separation of the friction preventing member 180 in
a direction toward the inner opening surface 166e of the first key recess 146 is suppressed.
[0113] Here, as shown in FIG.6, a height of the friction preventing member 180 in the axial
direction may be at least equal to a depth of the first key recess 166. However, the
height of the friction preventing member 180 in the axial direction may be slightly
smaller than the depth of the first key recess 166.
[0114] Meanwhile, as described above, the second key recess may be formed in the second
frame so that the second key portion of the Oldham ring is slidably inserted. FIGS.
7 and 8 are a perspective view showing a state that the frame and the wear preventing
member are separated from each other in FIG.3 and a plan view showing a combined state.
[0115] As illustrated, the second key recess 146 of the frame 140 and the second key portion
176 of the Oldham ring 170 may be formed to have the same shape as the first key recess
166 of the second scroll 160 and the first key portion 175 of the Oldham ring 170.
[0116] The second key recess 146 and the second key portion 176 and the friction preventing
member 180 inserted between the second key recess 146 and the second key portion 176
are different in an inner direction and an outer direction and have the same shape,
as compared with the first key recess 166, the first key portion 175, and the friction
preventing member 180 inserted between the first key recess 166 and the first key
portion 175 described above.
[0117] The shape of the friction preventing member 180 and the shape of the escape preventing
portion including the escape preventing recess 147 for preventing escape of the friction
preventing member 180 are also the same as those of the above-described embodiments.
Therefore, detailed description thereof will be omitted.
[0118] As described above, the scroll compressor according to the present embodiment has
the following operational effects.
[0119] That is, as the friction preventing members 180 are inserted between the first key
recess 166 and the first key portion 175 and between the second key recess 146 and
the second key portion 176, the first key portion 175 of the Oldham ring 170 is prevented
from coming into direct contact with the first key recess 166 of the second scroll
160 and the second key portion 176 of the Oldham ring 170 is prevented from coming
into direct contact with the second key recess 146 of the frame 140.
[0120] Accordingly, even though the second scroll 160, the frame 140, and the Oldham ring
170 are all made of the same material, particularly, formed of aluminum having a hardness
lower than that of cast iron, it is possible to suppress deterioration of the frictional
characteristics between the Oldham ring 170 and the second scroll 160 and between
the Oldham ring and the frame 140, thereby improving reliability of the compressor.
[0121] In addition, since the second scroll 160, the frame 140, and the Oldham ring 170
are all formed of a lightweight aluminum material, the weight of the compressor may
be reduced, and thus, efficiency of the compressor and efficiency of a device employing
the compressor such as a vehicle may be may be increased.
[0122] In addition, since the ring portion 171 and the key portions 175 and 176 of the Oldham
ring are formed as a single body, the connection portion between the ring portion
and the key portion may be sufficiently reinforced. Accordingly, the connection portion
between the ring portion 171 and the key portions 175 and 176 may be restrained from
being damaged by a force, thereby enhancing reliability of the compressor.
[0123] Since the ring portion 171 and the key portions 175 and 176 of the Oldham ring 170
are formed as a single body, a machining error between the ring portion 171 and the
key portions 175 and 176 or deformation at the key portions 175 and 176 may be minimized.
Accordingly, when the compressor is driven, distortion of the key portion in an undesired
direction in the key recess is minimized, thereby suppressing compression loss due
to a gap between the wraps.
[0124] In addition, since it is not necessary to form a separate coating layer on the surface
of the Oldham ring 170, it is possible to lower manufacturing cost of the Oldham ring
170 and suppress damage of the Oldham ring or a friction loss due to delamination
of the coating layer.
[0125] Meanwhile, in the above-described embodiments, the escape preventing recess may form
a kind of storage space. Thus, a certain amount of oil may be stored during the operation
of the compressor as well as when the compressor is stopped, and the stored oil may
flow between the key recess and the key portion, more precisely, between the key portion
and the friction preventing member to lubricate them. This may more effectively suppress
wearing of the key portion. Therefore, the bottom surface of the escape preventing
recess 167 may have the same height as the bottom surface of the first key recess
166 forming the third key recess 166c.
[0126] However, as shown in FIG.9, the depth of the bottom of the escape preventing recess
167 may be formed to be deeper than the depth of the bottom of the first key recess
166. Accordingly, an oil storage recess 167b may be formed on the bottom surface of
the escape preventing recess 167.
[0127] The oil storage recess 167b may be formed on the bottom surface of the escape preventing
recess as described above, but it is not necessarily limited to the escape preventing
recess. That is, the oil storage recess 167b may be formed outside the range of movement
of the key portion. For example, even though a separate escape preventing recess is
not formed, a semicircular recess is formed at the end of the key recess in terms
of machining, and the oil storage recess 167b may be formed in the recess.
[0128] When the oil storage recess 147b is formed in the escape preventing recess 147 as
described above, the oil flowing into the first key recess 166 is contained in the
oil storage recess 167b and a certain amount of oil may be supplied between the first
key recess 166 and the first key portion 175 during the operation of the compressor.
[0129] Meanwhile, in the above-described embodiment, the connection surface forming the
escape preventing protrusion is formed in a circular shape, or the connection surface
182 may be formed in a quadrangular shape as shown in FIG.10. In this case, it is
preferable that the escape preventing recess 167 is formed in the same shape as the
connection surface 182, that is, a quadrangular shape.
[0130] As described above, since the escape preventing recess 167 and the connection surface
182, i.e., the connection surface 182 forming the escape preventing protrusion, are
formed in a quadrangular shape, the radial bearing force for the friction preventing
member 180 may be further improved. As a result, it is possible to more effectively
suppress escape of the friction preventing member 180.
[0131] In addition, another embodiment of the structure for fixing the friction preventing
member according to the present invention is as follows.
[0132] That is, in the above-described embodiments, the connection surface of the friction
preventing member is inserted and fixed to the escape preventing recess, but in this
embodiment, the first and second reinforcement surfaces of the friction preventing
member are inserted into the escape preventing recess to support it. FIG.11 is an
exploded perspective view explaining another embodiment of an escape preventing portion
of a wear preventing member according to the present invention, and FIG.12 is a schematic
view for explaining an inner diameter of a key recess according to FIG.11.
[0133] As shown in this figure, in this embodiment, the escape preventing recess is not
formed on the outer side of the first key recess 166, and a first escape preventing
recess 166c1 is formed inside the first key recess167, that is, on an inner side of
the key recess surface 166a vertically in contact with the bottom surface, and a second
escape preventing recess 166c2 is formed on an inner side of the second key recess
surface 166b.
[0134] The first escape preventing recess 166c1 and the second escape preventing recess
166c2 are formed parallel to each other like the first key recess surface 166a and
the second key recess surface 166b, and an outer end of the first escape preventing
recess 166c1 and an outer end of the second escape preventing recess 166c2 are formed
to substantially coincide with the outer ends of the first key recess surface 166a
and the second key recess surface 166b.
[0135] A third escape preventing recess 166c3 is formed in such a manner that an inner side
is vertically in contact with the bottom surface of the first key recess 166. The
third escape preventing recess 166c3 connects inner ends of the first escape preventing
recess 166c1 and the escape preventing recess 166c2. The third escape preventing recess
166c3 is formed as a curved surface, but may be formed as a straight surface depending
on a case.
[0136] Here, the first escape preventing recess 166c1, the second escape preventing recess
166c2, and the third escape preventing recess 166c3 are formed to have the same depth
and are formed to have a depth such that one end of the friction preventing member
180 in the axial direction is inserted and supported.
[0137] As described above, even when the escape preventing recesses 166c1 to 166c3 for preventing
the friction preventing member 180 from escaping are formed inside the first key recess
166 instead of being formed outside the first key recess 166, it is possible to effectively
support escape of the friction preventing member 180.
[0138] Further, in this case, as viewed from the position of the second key recess, since
the escape preventing recess is not formed on the outer side of the second key recess
146 in the radial direction, the second key recess 146 may be moved to the outside
by the radius of the escape preventing recess. Accordingly, the inner diameter of
the Oldham ring 170 may be enlarged greatly to enlarge an inner diameter D1 of the
back pressure space 144. Accordingly, the area of the back pressure space 144 may
be enlarged to enlarge the area of a back pressure applied to the second scroll 160
and a behavior of the second scroll 160 may be stabilized.
[0139] In addition, another embodiment of the structure for fixing the friction preventing
member according to the present invention is as follows.
[0140] That is, in the above-described embodiments, the friction preventing member is fixed
using the escape preventing recess provided around the key recess, or the wear preventing
member is fixed with a separate fixing pin as in the present embodiment.
[0141] For example, as shown in FIGS. 13 and 14, a fixing pin 185 may be press-fitted to
the inner side of the connection surface 182 of the friction preventing member 180,
which is the deepest side of the first key recess 166, that is, farthest from the
center, and the connection surface 183 of the friction preventing member 180 may be
supported in the radial direction by the fixing pin 185.
[0142] In this case, it is not necessary to form an additional escape preventing recess
in the periphery of the first key recess 166, and it is not necessary to enlarge the
connection surface of the friction preventing member. Therefore, even in this case,
it is easy to machine the key recess and to manufacture the friction preventing member.
[0143] Further, in this case as well, from the viewpoint of the second key recess, it is
not necessary to form a separate escape preventing recess, and thus, the inner diameter
of the Oldham ring may be enlarged, thereby enlarging the area of the back pressure
space to stabilize the behavior of the second scroll.
[0144] In addition, another embodiment of the structure for fixing the friction preventing
member according to the present invention is as follows.
[0145] That is, in the above-described embodiments, the friction preventing member is provided
only on both the key recess surfaces of the key recess. However, in this embodiment,
the friction preventing member is provided on the bottom surface as well as on both
the key recess surfaces of the key recess. FIGS. 15 and 16 are a perspective view
and an assembled plan view of another embodiment of a wear preventing member according
to the present invention.
[0146] As shown in the figure, the friction preventing member 180 according to the present
embodiment may include a first reinforcement surface 181a, a second reinforcement
surface 181b, and a third reinforcement surface 181c formed between the first reinforcement
surface 181a and the second reinforcement surface 181b.
[0147] The first reinforcement surface 181a and the second reinforcement surface 181b are
formed in parallel to each other and the third reinforcement surface 181c is bent
from one axial end where first reinforcement surface 181a and the second reinforcement
surface 181b face each other to extend in the circumferential direction to connect
the first reinforcement surface 181a and the second reinforcement surface 181b.
[0148] The third reinforcement surface 181c corresponds to the bottom surface of the first
key recess 166. Accordingly, the friction preventing member 180 is formed to cover
the entire inner surface of the first key recess 166, except for the axial opening
surface 166d of the opened first key recess 166.
[0149] Here, in the first reinforcement surface 181a and the second reinforcement surface
181b, escape preventing surfaces 184a and 184b may further be formed to be bent from
the facing one ends of the first reinforcement surface 181a and the second reinforcement
surface 181b in the circumferential direction to radially supporting the friction
preventing member 180.
[0150] The escape preventing surfaces 184a and 184b may be formed in an arc shape extending
from the first reinforcement surface 181a and the second reinforcement surface 181b,
respectively. In this case, the above-described escape preventing recess 167 are formed
on the inner side of the first key recess 166 in the radial direction so that the
both escape preventing surfaces 184a and 184b may be brought into close contact with
the inner surface of the escape preventing recess 167.
[0151] In this case as well, it is also possible to form an escape preventing recess (not
shown) on the bottom surface of the first key recess 166 to insert the third reinforcement
surface 181c into the escape preventing recess, and the first reinforcement surface
181a and the second reinforcement surface 181b may be resiliently compressed to the
first key recess surface 166a and the second key recess surface 166b using the third
reinforcement surface 181c.
[0152] As described above, when the friction preventing member 180 is formed of the first
reinforcement surface 181a, the second reinforcement surface 181b, and the third reinforcement
surface 181c, the friction preventing member 180 covers even the third key surface
175c corresponding to the bottom surface of the first key recess 166, as well as the
first key surface 175a and the second key surface 175b of the first key portion 175.
Accordingly, even though a phenomenon that the second scroll 160 which is an orbiting
scroll tilts during a process of an orbiting movement, direct contacting between the
bottom surface of the first key recess 166 and the third key surface 175c of the first
key portion 175 may be suppressed.
[0153] In the above-described embodiments, although the example in which the Oldham ring
is provided between the frame and the orbiting scroll and is slidably engaged with
the frame and the second scroll has been described, but the Oldham ring may be slidably
coupled to the key recess provided in the fixed scroll and the key recess provided
in the orbiting scroll between the fixed scroll and the orbiting scroll.
[0154] Although the electric scroll compressor in which the casing is installed in the horizontal
direction has been described in the above embodiments, the present invention may also
be applied to a general scroll in which the casing is installed in a longitudinal
direction.
[0155] In the above-described embodiments, the low-pressure type scroll compressor in which
the internal space of the casing is formed as the suction space has been described.
However, the present invention may be equally applied to a high-pressure type scroll
compressor in which an internal space of the casing forms a discharge space.
[0156] The foregoing embodiments and advantages are merely exemplary and are not to be considered
as limiting the present disclosure. The present teachings may be readily applied to
other types of apparatuses. This description is intended to be illustrative, and not
to limit the scope of the claims. Many alternatives, modifications, and variations
will be apparent to those skilled in the art. The features, structures, methods, and
other characteristics of the exemplary embodiments described herein may be combined
in various ways to obtain additional and/or alternative exemplary embodiments.
[0157] As the present features may be embodied in several forms without departing from the
characteristics thereof, it should also be understood that the above-described embodiments
are not limited by any of the details of the foregoing description, unless otherwise
specified, but rather should be considered broadly within its scope as defined in
the appended claims, and therefore all changes and modifications that fall within
the metes and bounds of the claims, or equivalents of such metes and bounds are therefore
intended to be embraced by the appended claims.